Pedestrian traffic signals are presently in widespread use. Most pedestrian traffic signals are of the type which include a rectangular case, and a face plate mounted on the case which has an upper portion bearing the legend "DONT" and a lower portion bearing the legend "WALK". In the neon-type of traffic signal, neon tubes are mounted within the case, and the neon tubes are selectively energized at relatively high voltage by transformers which are also mounted in the case. When one of the neon tubes is energized, the words "DONT WALK" on the face plate are illuminated in a first color; and when another of the neon tubes is energized, only the word "WALK" on the face plate is illuminated in a second color. In accordance with Federal Standardization Procedures, in order to avoid confusion with vehicular traffic signals, the first color has been selected to be Portland orange, and the second color to be lunar white.
The invention of the copending application provides a pedestrian traffic signal unit which may be mounted in an existing neon tube rectangular case. The unit includes a housing shaped, as described, and which contains two incandescent lamps respectively mounted in the two compartments of the housing. Since the incandescent lamps operate at relatively low voltage, as compared with neon tubes, no transformers are required in the case. In a constructed embodiment of the invention of the copending application, 116 watt incandescent lamps have been found to provide the light intensity required for normal operation, and the lamps may be directly energized by the 120-volt 60 Hz electric mains.
Incandescent lamps are constructed to have an arcuate filament which is supported within the lamp envelope on appropriate wire supports, the wire supports also supplying the electric current to the filament. It has been found that for long life, the incadescent lamp must be supported in an angular position, such that the arcuate filament hangs down from the wire supports. For this reason, various attempts have been made in the past to provide rotatable sockets for the incandescent lamps, so that they may be rotated to their correct angular position. The objective of the present invention is to provide such a rotatable socket which is simple in its construction, and which is easy to operate.